Bob - S50

I've only run one tank dry. I did something similar to Paul, except I was watching the fuel pressure indicator. Yes, it began to vary before the engine quit. I too, switched tanks as soon as I saw that. The engine never quit. And as I've stated here before, our Aerospace Logic FL202 gauge, provided input by our Cies floats, showed the tank had 0.0 gallons left about 5 minutes before that happened. That's probably because some of the 'unusable' fuel in the tank is in fact usable in level flight.

Cies floats are not capacitance. I think they work on something called the Hall effect. Our gauges are consistently accurate to within .3 gallons/tank.

Remove all doubt. Install Cies and a digital gauge. My gauge/fuel counter total always stay within a gallon of each other. I believe whichever says I have the least gas.

Maybe I don't get it. I can't remember the last time I cared about making a standard rate turn. AC 91-75 allows you to replace a TC with an AI as long as it has a separate power supply. There is still a requirement to have a skid/slip ball but not a rate of turn indicator.

It's not the manufacturers and FAA that should be ashamed, it's the owners who are (understandably) unwilling to spend the money to put in a system that works. I suspect the newer aircraft being built either already do (cirrus) or will eventually come with accurate systems.

Our gear doors are filthy but that's from oil coming out the crankcase vent. Nothing inside the compartment though. Do you actually have black oil on the firewall and other parts inside the cowl?

We are a few hundred hours away from the same decision. Here is my reasoning: A. If we keep the A3B6D engine. Get it overhauled locally. Get it overhauled by an engine specialty shop. Do an overhaul exchange. That could be Lycoming or a few of the specialty shops. The decision comes down to cost, down time, and quality of work (mostly based on reputation). B. Switch to an A3B6 engine (my personal preference). Probably cannot do that locally, and also probably leaves out many of the smaller specialty shops. Do an overhaul exchange as in A above. C. Do an overhaul exchange with Lycoming to an IO390. I don't like the 390 idea because it also involves a different prop which really drives the price up. And the 10 extra HP means I'll have to get a high performance endorsement because the F15 and 767 I flew aren't high performance. Also, I personally believe (from what I've read here and other sources) that I'm less likely to get a quality product from Lycoming than a specialty shop. Whoever does the work, I want to have the engine dynamically balanced. If the shop can't do that I'll move on. This kind of eliminates Lycoming. The engine is not something I want to go cheap on and balancing will make it run smoother, make the ride more enjoyable, and reduce vibration damage to other parts/equipment. Why keep the A3B6D? Probably the cheapest way to get an overhaul done. Why not keep the A3B6D engine? Getting harder to find parts for the magneto. When that becomes impossible, the engine becomes a core for a trade in regardless of the hours since OH. Why OH exchange for a A3B6? The exchange minimizes my down time. Gets rid of the dual magneto. Allows me to get an electronic ignition for one side. I believe most A3B6 engines are timed to 20 BTDC vs 25 for the D engine. I believe this will reduce CHT's, reduce blowby (oil consumption and belly filth), and allow me to operate smoothly at lower RPM's (closer to or over square). Why not an A3B6? I believe that the 20 BTDC timing will generate slightly less power when firewalled so takeoff roll will be slightly longer and initial climb will be slightly less. However, with an electronic ignition, by the time I get up to 5000' I will have recovered that power and will have better performance as I continue to climb. And of course, it will also probably cost a little more by the time the engine is hung and ready to fly.

You can find out by reading these: M20C Review M20E Review M20F Review

$$$ limited. Specific will always work better than an all in one.

I assume the AV20-S is mounted on the panel that is at a slight angle to the main panel. Please let me know how the AI function works there. I'm considering doing the same thing but I'm worried that being mounted at an angle might induce a pitch error during turns. I'm thinking a left bank might make the pitch go up a couple degrees while a bank to the right might make the pitch go down a couple degrees.

If you really are looking for the BEST (maximum?) TAS, that will always occur at the highest altitude that will allow you to make your desired power. That is, for an NA airplane, the theoretical altitude for 75% power is about 7500'. For 70% it is about 9500'. For 65% power it is about 11,500'. The actual altitude may be just a bit lower due to pressure loss in the induction system caused by the air filter and friction. When we used to have a Bracket air filter, we lost about 1 or 2 inches of MP compared to the Donaldson we use now. That means our best altitude was lower for the Bracket. That said, on short trips I like 3500 - 5500. On medium length trips I like 5500 - 7500. On long trips I like 8500-10500. However, if the ride sucks I'll go up to 12,500 if that will give me a smooth ride.

Yes, 100% of usable is usable, at least in level flight it is. On my J not only will it burn all the usable fuel, it will burn a bit over half of the unusable.

Depending on how much you like doing math in your head, 1.5%/1000' is actually closer. So 9500 (close to 10) is about 15%. 15% of 135 is 13.5+ about 7. That's about which equals about 20 or 21 MPH. That would make it about 155 TAS.

Because the altitudes shown on FlightAware what you would see if your altimeter was set to 2992. It looked like he was inside the Class B by about 400 feet on his way out. If the altimeter was 2950, he could have been right at the base even though FlightAware showed 5400.

I agree that the 1.5 gallons out of the left wing was most likely due to trapped air. If the same thing happened on the right then you only burned 8.5 gallons, not 10. I don't dawdle on the ground. For me, it's usually about 7 minutes from start to takeoff for the first flight of the day and more like 3 or 4 minutes on subsequent flights. I plan on burning .5 gallons for start, taxi, and takeoff. If you spend more time than me then you may burn closer to a gallon. At any rate, you are down to about 8 gallons burned. For climb, I figure it costs me a quart of gas to climb 1000'. That means you probably spent about 1 to 1.25 gallons for the climb. That leaves about 7 gallons burned in cruise. That's still a lot for a 32 minute flight, but not unreasonable if you were well ROP. If you were running 2050 RPM and 24" MP, that is well over square and I'm guessing you didn't even get close to peak EGT before the engine appeared to run rough (because I'm guessing it was more like lugging the engine). So I'm guessing you were in fact well ROP. Do you have an EGT gauge? Did you reference it while leaning? Next time, instead of 2050 RPM and 24", try it the other way around: pull the MP back to 20" and then reduce the RPM to 2400 (about the same power). After you reduce RPM you'll probably notice the MP has risen so pull it back to 20" again, then lean to roughness and enrichen until smooth. See how that affects your burn.

Looking at FlightAware, it looks like he was in the Class B surface area for about 2 minutes. Depending on the altimeter setting, he may have busted the Class B 5000' floor on the way out of town headed home too. If the altimeter was up around 3030 or higher then he was probably OK. Ooops. Got that backwards. If his altimeter was below about 29.50 he should be OK.

I understand that the pitch changes to prevent overspeed. But are both of you telling me I cannot get 2700 RPM on the ground with less than full power? Seems to me that as power is increased the RPM goes up just like it does for the magneto check. When there is enough power to rotate the engine at 2700 RPM, adding more power will result in higher pitch to prevent overspeed. In my mind, a constant speed prop is a fixed pitch prop until RPM reaches that selected by the prop control. I can see why a ground static run would indicate power for a fixed pitch prop, but not for a constant speed prop. I guess I don't understand how our props work. Edit: I think I now understand what you are saying. You are saying that the flat pitch angle is set such that it will in fact require full power to get to 2700 RPM during a static run. As speed increases, the pitch increases to maintain that RPM.

I would think that just because an engine with a constant speed prop makes 2700 RPM, it doesn't mean it's making 200 HP.

Just my opinion, but putting an MSC label on a shop does not guarantee they do the best work. The quality of the work is more dependent on those turning the wrench than whether or not they are an MSC. An MSC that is good can take a turn for the worse if there is a change in mechanics. Likewise, one that was not so great can get better with new mechanics or more experience. I'd rather go to a non-MSC with good mechanics than an MSC with average mechanics. The hard part is finding out which is which. Good job finding and fixing your leak.

If it took 2000' to get airborne then you are not making full power. Could be low RPM, low MP, incorrect mixture, or incorrect magneto timing.

We've found on our J that the drilled hole is the reference point for 25 gallons. Makes it a lot easier to see when filling too.

Unuseable is defined in the POH.

Unuseable fuel is determined under specific conditions. That doesn't mean you cannot use it under other conditions. I ran one tank down until our Cies input digital gauge said zero. The engine ran another 5 minutes at cruise power.

I would add one caveat to that. Keep track of how many total customers they have done work for. Using a 5 star rating system, since satisfied customers usually do not take time to rate an experience, assume any customer who did not give them a rating was a 4.5 star customer. Include those ratings when determining an overall rating for the shop/product. Just looking at the number complaints would not necessarily paint an accurate picture. If two shops have 10 complaints against them in a year, but one shop only did 25 jobs while the other did 500, I'd say the first shop looks pretty bad while the second looks pretty good.

When we weighed our plane in 2013 we did it with fuel in and subtracted the fuel weight. After all the equipment changes for the GFC500 install and other changes we'd made in between, I realized we might have made as much as an 8 pound error in our calculations. We decided to re-weigh the plane with no useful fuel on board, just the 1.25 gallons/wing as specified in the procedure. We gained 18 pounds of useful load. As for the 5.82 lbs/gallon, I had done some looking on line and found specs for a few manufacturers: Epic says their relative density is .65 to .75 at 15C. If you take the average of that, .7, it gives you a value of 5.84 lbs/gallon. Phillips says theirs weighs 5.83 lbs/gallon. Shell says theirs weighs 700 to 730 Kg/M^3. Using 715, that translates to 5.97 lbs/gallon.